1. Field of the Invention
The present invention generally relates to prevention and extinguishment of fires of combustible materials by utilizing a composition of matter group which is highly efficient and environmentally friendly. More particularly, the invention relates to prevention and extinguishment of fires of combustible materials by using a group of fire suppressants having labile bonds between bromine atoms and atoms other than carbon.
2. Description of the Prior Art
Fire suppression by halogenated alkanes is well-established in both the scientific literature and commercial practice as taught, for example, in R. G. Gann ed., Halogenated Fire Suppressants, ACS Symposium Series 16 (American Chemical Society, Washington, D.C.) 1975. The two most widely used halogenated suppressants are Halon 1301 (CF.sub.3 Br) and Halon 1211 (CF.sub.2 ClBr). These compounds are very stable, so they survive long enough in the troposphere to be gradually transported to the stratosphere, where they are photolyzed by solar ultraviolet radiation to produce free radicals that catalyze ozone depletion as taught, for example, in J. G. Anderson, D. W. Toohey, and W. F. Brune, Science, 251, 39 (1991). Production of these materials has therefore been internationally prohibited after January, 1994 by the Montreal Protocol on Substances that Deplete the Ozone Layer. The problem is therefore to find fire suppression materials and methods which are at least as effective as Halon 1301 and Halon 1211 but which do not deplete the ozone layer.
Representative of the prior art directed to the use of fluorocarbons which have no chlorine or bromine is U.S. Pat. No. 5,236,611 (Shiflet). These fluorocarbons are slowly transported into the stratosphere, but the catalytic efficiency of fluorine is very much smaller than that of chlorine, bromine, or iodine.
Representative of the prior art directed to the use of hydrogenated halocarbons, which are less stable than Halon 1301 or Halon 1211 in the troposphere, are U.S. Pat. Nos. 5,084,190 (Fernandez), 5,135,054 (Nimitz et al.); 5,093,013 (Sprague); and 5,080,177 (Robin et al.). It is well known that Halons containing chlorine or bromine will suppress fires in smaller quantities than those which contain only fluorine. However, it is understood by people practiced in the art of combustion that the principal source of heat release in hydrocarbon combustion is oxidation of hydrogen atoms to form water vapor. Thus hydrogenated halocarbons are expected to act chemically both as fuels and as fire suppressants.